Put the chocolate and the rum to a bowl that is placed on top of a pan with barely simmering water; stir occasionally and melt.
While the chocolate is cooling down, beat with an electric mixer the butter with half of the sugar till it is nice and creamy.
Add the egg yolks; beat some more.
Preheat an oven to 180 degrees and grease a baking tin. I used a silicon 29 cm heart shaped form, but it can be replaced by a 20-22cm diameter round tin with a removable bottom. If you are using the round tin, additionally put a disc of baking paper on its bottom.
Whisk the egg whites with the salt until soft peaks form; add the rest of sugar and whisk till stiff.
Add to the butter mixture the cooled down melted chocolate and the ground almonds, stir well.
Now add 1 tbsp of whisked egg whites and 1 tbsp of the flour, stir gently. Repeat till you have used all the flour; at the end add the rest of the whisked egg whites and mix gently again.
Pour the batter to the prepared form, put it to the oven and bake for 20 minutes.
Put the raspberries in a blender and liquidise them; then press through a fine sieve to eliminate the pits and mix with the vanilla sugar.
Prepare the gelatine as per its packet instruction.
Whisk the double cream until stiff, slowly add the sugar.
Add a few tablespoons of the liquidised raspberries to the pan with dissolved gelatine, stir and then add the rest of the raspberries.
Combine the cream with the raspberries.
Keep the baked base in the tin and when it is cold, pour the raspberry mousse to the tin, smooth the top and put the cake to the fridge for a few hours, preferably overnight.